Pretty fun idea and a well-implemented game to play. Mechanics wise there are a lot of things to polish but this is a good start. Also, I noticed that there's no use of those gems collected which ruins up the feel. You can also try implementing a good art style to this game to make it look unique and charming. Along with that, there are a lot of other things to test and scale-up. All the best, will checkout again in the near future.